Spatial contrast sensitivity was measured in normal subjects with and without retinally-stabilized artificial central scotomata of varying diameters. Small artificial scotomata produced a middle and high spatial frequency loss in sensitivity. For larger scotomata, the type of loss obtained depended on temporal factors associated with grating presentation. A predominantly high spatial frequency loss was observed if grating contrast was turned on and off gradually. An additional low frequency loss was obtained under conditions in which grating contrast was turned on and offf abruptly.